Unrestrained rotor

ABSTRACT

A rotor structure for a rotary regenerative heat exchanger is defined wherein the rotating elements of a rotor subject to differential thermal expansion and to a concentration of stresses that effect cracking and failure of the usual welded joints therebetween are replaced by pivotal connections that allow relative movement sufficient to accommodate thermal expansion and thus preclude structural failure.

United States Patent 1 Kurschner et al.

1 1 Jan. 16,1973

[541 UNRESTRAINED ROTOR [75] Inventors: Hermann E. Kurschner; RobertEmmett Mahoney, both of Wellsville,

[73] Assignee: The Air Preheater Company, Inc.,

Wellsville, NY.

[22] Filed: Aug. 4, 1971 [2]] Appl. No.: 168,877

[52] U.S. Cl. ..165/9, 165/10, 64/17 [51] Int. Cl ..F28d 19/04 [58]Field of Search ..l65/8, 9, 10; 64/17 [56] References Cited UNITEDSTATES PATENTS 3,216,486 11/1965 Hall et a] ..l65/8 3,369,593 2/1968Brandt 165/10 3,572,425 3/1971 Brandt ct al .0 105/) FOREIGN PATENTS ORAPPLICATIONS 1,136,087 12/1968 Great Britain 165/10 PrimaryExaminer-Albert W. Davis, Jr. Attorney-Wayne 1-1. Lang et a1.

[ 5 7 ABSTRACT A rotor structure for a rotary regenerative heatexchanger is defined wherein the rotating elements of a rotor subject todifferential thermal expansion and to a concentration of stresses thateffect cracking and failure of the usual welded joints therebetween arereplaced by pivotal connections that allow relative movement sufficientto accommodate thermal expansion and thus preclude structural failure.

9 Claims, 7 Drawing Figures UNRESTRAINED ROTOR SUMMARY OF THE INVENTIONIn rotary regenerative heat exchange apparatus a rotor having radialcompartments that carry a mass of heat absorbent material rotatesalternately between a hot and a cold fluid in order that heat absorbedfrom the hot fluid may in turn be transferred to the cold fluid flowingtherethrough.

The rotor is surrounded by a housing formed with end plates at spacedends that have openings to simultaneously direct the heating fluid andthe fluid to be heated through spaced compartments of the rotor.

Rotary regenerative heat exchange apparatus is effective and widely usedbut it is especially effective for applications having small overallsize and operating at modest temperature differentials where thermaldeformation is not significant.

Inasmuch as the present trend is toward the use of large heat exchangersthat operate at high temperatures having significant thermaldeformation, it is becoming increasingly difficult to maintain thestructural integrity of the heat exchanger. This is mainly true becauseexcessive thermal deformation of the component parts results in acracking or breaking of the welded joints therebetween and the eventualfailure of the structural apparatus.

This invention therefore, provides an arrangement whereby the rotor of arotary regenerative heat exchanger is comprised of independentsector-shaped baskets pivotally supported by a rotatable rotor postwhereby movement effected by thermal expansion or contraction of oneelement thereof is not transmitted to a member adjacent thereto, andwhereby the concentration of stresses as effected by a differential ofexpansion does not cause the cracking or breakage of weldments andultimate failure of the rotor structure. While the apparatus isoperating under near constant conditions that do not produce excessiveexpansion of parts or the excessive concentration of stress, the rotoris firmly supported by the central rotor post in a manner that precludesrelative movement between its component parts.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional elevation of aheat exchanger constructed in accordance with the invention,

FIG. 2 is an enlarged detail as seen from line 2-2 of FIG. 1 showing anarrangement by which sector-shaped rotor compartments are pivoted to therotor post,

FIG. 3 is an enlarged cross-sectional view showing the details ofatypical pivotal basket attachment,

FIG. 4 is a perspective view of an individual element basket,

FIG. 5 is a perspective view of a sealing arrangement extending aroundaxially spaced layers of the rotor,

FIG. 6 is a.perspective view in section of a radial seal including acutaway side panel of an adjacent basket, and

FIG. 7 is a perspective view of a radial sealing arrangement betweenaxially spaced basket layers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The arrangement of the drawingshows a rotary regenerative heat exchanger having a horizontal rotorpost 12 supported by bearings 14 and rotated about its axis by means ofthe drive motor 16 that is connected through a suitable reductiongearing to the rotor post. A mass of heat absorbent material 18 iscontained in independent, open ended, sector-shaped containers orbaskets 22 are secured to the rotor post by pivotal attachments 24 toform a composite rotor 26 that upon rotation within the surroundinghousing 28 is adapted to intermittently coincide with the spacedopenings 32, 34, 35 and 37 in opposite ends of the surrounding rotorhousing whereby fluids passing through the housing are directed throughthe heat absorbent material of the ro lIOI.

While the entire rotor is subjected to alternating extremes oftemperature, it has been found that the inner ends of baskets thatcomprise the portion of the rotor adjacent the rotor post are subjectedto greater temperature variation than the radial outer ends, thereforemaximum thermal expansion occurs adjacent the rotor post. Moreover, theadjacent rotor post operates continuously in a relatively coolatmosphere so there is considerable differential of expansion betweenthe rotor and the rotor post. Thus the usual welded or other type ofintegral joint used to connect the rotor to the rotor post is subjectedto a differential of expansion and unequal stresses that producescracking and breaking of the weldment and destruction of the structure.Therefore, according to this invention the radial inner ends of thebaskets are pivotally secured by universal joints to the rotor post topermit limited relative move ment therebetween, while the radial outerends of adjoining baskets that are subjected to little relative thermaldeformation may be connected by bolts 42 into an integral annular shellthat surrounds the rotor.

Circumferential seals 38 positioned around the end edges of the rotorand axial sealing means 44 shown in FIG. 5 of the leaf-type are held toflanges 43 at the arcuate ends of adjacent baskets so they extendoutwardly and rub against the surrounding rotor housing 28 to precludethe flow of air through the space therebetween during its passagebetween the inlet and the outlet. The bolts 42 that connect adjoiningbaskets also hold the axial seals 44 in position at the periphery of therotor. Sealing means 40 shown in FIG. 6 extending radially betweenbaskets from the inner to the outer ends of the rotor are adapted toreach axially thereof sufficient to bridge the space between theadjacent end parts of the rotor and the rotor housing. The radial seals40 are connected by bolts 45 to only one of adjacent baskets while theother is cutaway in the manner shown at 49 in FIGS. 4 and 6 to providefreedom of movement. Thus, each basket is secured to baskets ad jacentthereto only at the ends of the arcuate outer wall so as to provide anintegral annular shell extending around the rotor. At the same time, theradial sides of each basket are entirely independent from each adjoiningbasket and are thus free to expand or contract laterally withoutinterference while each sector-shaped basket is secured by a pivotalattachment 24 to the rotor post 12 to provide adequate support thereforbut to permit limited relative movement therebetween.

If the difference in thermal expansion between the rotor post and thesurrounding rotor is substantial, or other conditions should promoteexcessive structural deformation of the rotor, a plurality of layers ofelement baskets, each independently pivoted to the rotor post, may beprovided to minimize the deformation of the rotor. In such anapplication as shown by FIG. 5 the axially spaced layers of element maybe joined by flexible sealing means 54 secured by bolts 56 to theflanges 58 that extend circumferentially around the arcuate peripheraledge of the rotor. Other sealing means 62 shown in FIG. 7 comprising anelongate bar with spring sections 64 on opposite sides thereof adaptedto abut adjacent baskets may be inserted between baskets in axiallyspaced sections to limit the flow of fluid to the interior of theadjacent baskets so it will flow through and contact the heat absorbentelement carried thereby.

While this invention has been described with reference to the thermalembodiments illustrated in the drawing, it is evident that numerousother changes may be made without departing from the spirit of theinvention, and it is intended that all matters contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative and not in a limiting sense.

We claim:

1. Rotary regenerative heat exchange apparatus having a central rotorpost, a plurality of baskets arranged in juxtaposition around the rotorpost to comprise a rotor, a mass of heat absorbent material contained inthe baskets of the rotor, housing means surrounding the rotor includinginlet and outlet ports for a heating fluid and a fluid to be heated,means for rotating the rotor about its axis, and pivotal connectionssecuringbaskets to the rotor post to accommodate relative movementtherebetween.

2. Rotary regenerative heat exchange apparatus having a horizontal rotorpost, bearing means supporting said rotor post for rotation about itshorizontal axis, a plurality of sector-shaped baskets arranged injuxtaposition around the rotor post to comprise an annular rotor, a massof heat absorbent material carried in the baskets of the rotor, housingmeans surrounding the rotor having inlet and outlet ports for a heatingfluid and the fluid to be heated, means for rotating the rotor about itsaxis whereby the sector-shaped baskets are alternately aligned with theinlet and outlet ports for the heating fluid and the fluid to be heated,means connecting the outer wall of each basket to baskets adjacentthereto to form a composite rotor with an outer annular wall concentricto the rotor post, and a pivotal coupling securing each basket to therotor post whereby there may be relative movement therebetween.

3. Rotary regenerative heat exchange apparatus having a central rotorpost as defined in claim 2 wherein the rigid annular wall around therotor post is concentric thereto.

4. Rotary regenerative heat exchange apparatus including a central rotorpost and a composite rotor shell as defined in claim 2 having radialsealing means intermediate adjacent baskets extending axially toward theend plates of the surrounding housing to bridge the leakage aththerebetween.

5. o ary regenerative heat exchange apparatus including a central rotorpost and a surrounding rotor as defined in claim 4 wherein each radialsealing means is affixed to only one of the adjacent sector-shapedcompartments of the rotors.

6. Rotary regenerative heat exchange apparatus including a central rotorpost and a composite rotor shell as defined in claim 2 wherein thepivotal couplings joining the sector-shaped baskets to the rotor postlie at a midpoint between the edges of the face of the adjacent rotorbasket.

7. Rotary regenerative heat exchange apparatus having a horizontal rotorpost, a plurality of sector-shaped baskets with axially open endsarranged in radial juxtaposition around the rotor post to provide anannular basket layer, a plurality of layers of said baskets axiallyspaced along the rotor post, a mass of heat absorbent material carriedin the baskets of the rotor, housing means including inlet and outletports for heating fluid and a fluid to be heated surrounding the rotor,means for rotating the rotor about its axis within the rotor housing, auniversal joint securing each basket of the rotor to the rotor post, andflexible sealing means joining the arcuate periphery of the axiallyspaced layers of the rotor to preclude fluid leakage while permittingrelative movement therebetween.

8. Rotary regenerative heat exchange apparatus as defined in claim 7having means joining the periphery of radially adjacent baskets into anintegral shell concentric with the rotor post.

9. Rotary regenerative heat exchange apparatus as defined in claim 7including axial sealing means lying between ends of radially adjacentbaskets and extending radially to bridge the space between the rotor andsurrounding rotor housing to preclude fluid flow therebetween.

1. Rotary regenerative heat exchange apparatus having a central rotorpost, a plurality of baskets arranged in juxtaposition around the rotorpost to comprise a rotor, a mass of heat absorbent material contained inthe baskets of the rotor, housing means surrounding the rotor includinginlet and outlet ports for a heating fluid and a fluid to be heated,means for rotating the rotor about its axis, and pivotal connectionssecuring baskets to the rotor post to accommodate relative movementtherebetween.
 2. Rotary regenerative heat exchange apparatus having ahorizontal rotor post, bearing means supporting said rotor post forrotation about its horizontal axis, a plurality of sector-shaped basketsarranged in juxtaposition around the rotor post to comprise an annularrotor, a mass of heat absorbent material carried in the baskets of therotor, housing means surrounding the rotor having inlet and outlet portsfor a heating fluid and the fluid to be heated, means for rotating therotor about its axis whereby the sector-shaped baskets are alternatelyaligned with the inlet and outlet ports for the heating fluid and thefluid to be heated, means connecting the outer wall of each basket tobaskets adjacent thereto to form a composite rotor with an outer annularwall concentric to the rotor post, and a pivotal coupling securing eachbasket to the rotor post whereby there may be relative movementtherebetween.
 3. Rotary regenerative heat exchange apparatus having acentral rotor post as defined in claim 2 wherein the rigid annular wallaround the rotor post is concentric thereto.
 4. Rotary regenerative heatexchange apparatus including a central rotor post and a composite rotorshell as defined in claim 2 having radial sealing means intermediateadjacent baskets extending axially toward the end plates of thesurrounding housing to bridge the leakage path therebetween.
 5. Rotaryregenerative heat exchange apparatus including a central rotor post anda surrounding rotor as defined in claim 4 wherein each radial sealingmeans is affixed to only one of the adjacent sector-shaped compartmentsof the rotors.
 6. Rotary regenerative heat exchange apparatus includinga central rotor post and a composite rotor shell as defined in claim 2wherein the pivotal couplings joining the sector-shaped baskets to therotor post lie at a midpoint between the edges of the face of theadjacent rotor basket.
 7. Rotary regenerative heat exchange apparatushaving a horizontal rotor post, a plurality of sector-shaped basketswith axially open ends arranged in radial juxtaposition around the rotorpost to provide an annular basket layer, a plurality of layers of saidbaskets axially spaced along the rotor post, a mass of heat absorbentmaterial carried in the baskets of the rotor, housing means includinginlet and outlet ports for heating fluid and a fluid to be heatedsurrounding the rotor, means for rotating the rotor about its axiswithin the rotor housing, a universal joint securing each basket of therotor to the rotor post, and flexible sealing means joining the arcuateperiphery of the axially spaced layers of the rotor to preclude fluidleakage while permitting relative movement therebetween.
 8. Rotaryregenerative heat exchange apparatus as defined in claim 7 having meansjoining the periphery of radially adjacent baskets into an integralshell concentric with the rotor post.
 9. Rotary regenerative heatexchange apparatus as defined in claim 7 includIng axial sealing meanslying between ends of radially adjacent baskets and extending radiallyto bridge the space between the rotor and surrounding rotor housing topreclude fluid flow therebetween.